Biomedical subjects

E Vázquez

Publications and source records attributed to E Vázquez.

At least 19 recordsLinked to original sources

PubMed2003

Hypotension, acidosis and vasodilation syndrome after heart transplant: incidence, risk factors, and prognosis.

BACKGROUND: HAV syndrome, the combination of hypotension, acidosis and vasodilation (HAV), is a serious postoperative complication after heart transplantation (HT). Its etiology and prognosis are poorly understood. AIM: To determine the incidence and prognosis of post-HT HAV syndrome and examine possible risk factors. METHODS: Retrospective examination of the records of 85 consecutive patients who underwent HT between December 1999 and June 2002 sought the HAV criteria: systolic BP <85 mm Hg plus HCO3 <19 mEq/l whole excluding cardiogenic, hypovolemic and septic shock. Donor variables included sex, age, weight, height, cause of death, time in ICU, and ischemic time; while recipient variables, sex, age, weight, height, etiology of cardiopathy, previous cardiopulmonary bypass surgery, preoperative amiodarone, beta-blockers, catecholamines, mechanical ventilation or intra aortic balloon pump (IABP), RVP, time on waiting list, pump time, reoperations, polytransfusion, preoperative creatinine, GOT, GPT and GGT, induction with OKT3 or anti-CD25, bypass-to-HAV time, duration of catecholamine treatment, and 1 month survival after HT. RESULTS: The 11 HAV cases (13%) appeared between 1 and 72 h after HT (75% in the first hour). Catecholamines were used for 1 to 6 days; control was achieved within 48 h in 58% of cases. Two HAV patients (18%) died within the first month versus six non-HAV patients (8.1%) (P=.275). Only polytransfusion showed more than a borderline value to predict HAV syndrome. CONCLUSIONS: HAV syndrome has an incidence of 13% and a mortality of 18% within 1 month post-HT. The only likely risk factor is polytransfusion.

Acidosis↗

PubMed2003

Timing of first feeding and life-history strategies in salmon: genetic data.

To investigate the relationship between genetic composition and some physiological traits of interest (age at smoltification, precocious maturation in male parr) in early and late first feeding Atlantic salmon, genetic variation at 6 isozyme and 8 microsatellite loci was examined. Early and late first feeding salmon showed different allelic and genotypic distributions at both isozyme and microsatellite loci. A positive relation between enzymatic loci heterozygosity and precocious active alimentation and earlier smoltification (S1 cf. S2) were also found.

Alleles↗

PubMed2002

Effects of cocaine administration on VTA cell activity in response to prefrontal cortex stimulation.

The repeated use of psychostimulants in humans has been associated with progressive enhancement of anxiety, panic attacks, and eventually paranoid psychosis. The appearance of such behaviors has been termed behavioral sensitization, which forms part of the basic pathological mechanisms involved in drug addiction. Psychostimulants act via a circuit involving the ventral tegmental area (VTA), prefrontal cortex (PFC), and nucleus accumbens. The PFC sends glutamatergic projections that activate dopaminergic neurons in the VTA. These projections provide an extremely important excitatory drive necessary for the development of sensitization. The effects of cocaine administration on the response of dopaminergic VTA cells to activation of the PFC have not been reported. Here the effects of acute cocaine administration on VTA cell response to PFC stimulation are examined. Statistical analysis of the changes in spontaneous activity and evoked response revealed a significant decrease in spontaneous activity at 1.0 mg/kg i.v. after cocaine treatment compared to baseline levels. The net effect was an increase in signal-to-noise ratio. Treatment with MK-801 at a dose of 2 mg/kg showed that the excitatory response was, at least partially, NMDA-mediated. Prazosin pretreatment (0.5 mg/kg i.p.) did not prevent a significant decrease in spontaneous activity brought about by cocaine (15 mg/kg, i.p.). Nonetheless, prazosin alone induced a significant decrease in the response to PFC stimulation when compared to baseline. In addition, iontophoretic application of norepinephrine (NE) onto VTA cells revealed that NE potentiated (19.2%), enhanced (26.9%), or suppressed (46.2%) the glutamate-evoked response in VTA cells. The results suggest that a possible role of cocaine in the process of sensitization might be to amplify the PFC-induced excitation at the VTA. Since the iontophoretic release of NE in almost half of the sampled cells produced similar effects to those of cocaine it may suggest a possible NE-mediated mechanism for cocaine actions.

Animals↗

PubMed2002

[Platelet antiaggregation and hemorrhagic risk in hemodialysis].

UNLABELLED: Although the efficacy of antiplatelet therapy in the prevention of cardiovascular disease in chronic renal failure is not clearly defined, the improvement in cardiovascular disease outcomes in the general population has resulted in its use in dialysis patients. The hemorrhagic risk of hemodialysis patients treated with anti-platelet agents has not been clarified. Our aim was to evaluate the risk of bleeding in hemodialysis patients treated with antiplatelet agents. We assessed haemorrhagic complications (HC) in 190 haemodialysis patients from May 1998 to August 2000. HC was defined an event that required hospitalization and/or blood product transfusion. We evaluated the bleeding events in the haemodialysis patients treated with antiplatelet agents and compare them to those not receiving this therapy to establish the relative risk of bleeding. Uni- and multivariate analyses were conducted to establish the relationships between the haemorrhagic event and the following variables: age, gender, time on dialysis, dialysis membrane (synthetic or cellulosic), systemic anticoagulation during haemodialysis, anaemia (haematocrit), PTH, urea, dialysis efficacy (Kt/V), hypertension, diabetes, use of erythropoietin and antisecretory gastric agents. RESULTS: 81 (42.6%) were treated with antiplatelet agents. Of the 190 patients, 28 (14.7%) had 36 haemorrhagic events (10.3 episodes/100 patient-years); 31 digestive-tract haemorrhages, 4 intracranial and 1 pulmonary. Twenty (24.7%) of patients treated with antiplatelet agents had 16.2 episodes/100 patient-years and 8 (7.3%) without this therapy had 6 episodes/100 patient-years (p < 0.01). In the multivariate analysis the antiplatelet therapy remained associated with higher probability of having a haemorrhagic complication (OR 3.8; CI 95%: 1.52-9.76, p = 0.004). Older age (OR 1.03; CI 95%: 1-1.06, p = 0.043), anaemia (OR 0.91; CI 95%; 0.84-0.9, p = 0.027) and hypertension (OR 2.99; CI 95%: 1.05-8.48, p = 0.039) remained associated with the risk of bleeding. 88.2% of patients that had a digestive-tract haemorrhage with antiplatelet therapy were receiving an antisecretory agent (histamine H2-receptor antagonist or a proton-pump inhibitor). CONCLUSIONS: 1) dialysis patients with antiplatelet therapy had a higher haemorrhagic risk. The relative risk of bleeding was more than three times that of the dialysis population without antiplatelet therapy, and 2) older age and hypertension were associated with the haemorrhagic risk. Optimal correction of anaemia was associated with less probability of bleeding.

Adult↗

PubMed2001

Novel versatile fullerene synthons.

We report the synthesis of three novel, versatile fullerene intermediates whose main feature is the presence of an amino end group. Simple condensation reactions of these intermediates under standard conditions produce new derivatives that are useful for applications in materials science and medicinal chemistry.

Amines↗

PubMed2001

Defective regulatory volume decrease in human cystic fibrosis tracheal cells because of altered regulation of intermediate conductance Ca2+-dependent potassium channels.

The cystic fibrosis transmembrane conductance regulator (CFTR) protein has the ability to function as both a chloride channel and a channel regulator. The loss of these functions explains many of the manifestations of the cystic fibrosis disease (CF), including lung and pancreatic failure, meconium ileus, and male infertility. CFTR has previously been implicated in the cell regulatory volume decrease (RVD) response after hypotonic shocks in murine small intestine crypts, an effect associated to the dysfunction of an unknown swelling-activated potassium conductance. In the present study, we investigated the RVD response in human tracheal CF epithelium and the nature of the volume-sensitive potassium channel affected. Neither the human tracheal cell line CFT1, expressing the mutant CFTR-DeltaF508 gene, nor the isogenic vector control line CFT1-LC3, engineered to express the betagal gene, showed RVD. On the other hand, the cell line CFT1-LCFSN, engineered to express the wild-type CFTR gene, presented a full RVD. Patch-clamp studies of swelling-activated potassium currents in the three cell lines revealed that all of them possess a potassium current with the biophysical and pharmacological fingerprints of the intermediate conductance Ca(2+)-dependent potassium channel (IK, also known as KCNN4). However, only CFT1-LCFSN cells showed an increase in IK currents in response to hypotonic challenges. Although the identification of the molecular mechanism relating CFTR to the hIK channel remains to be solved, these data offer new evidence on the complex integration of CFTR in the cells where it is expressed.

Calcium↗

PubMed2001

Dietary gangliosides positively modulate the percentages of Th1 and Th2 lymphocyte subsets in small intestine of mice at weaning.

We studied the influence of dietary gangliosides on the number of spontaneous cytokine-secreting cells from two intestinal lymphocyte populations: lamina propria lymphocytes and Peyer's patches lymphocytes in Balb/c mice for 28 days after weaning. Weanling mice were separated into two groups, designated as Control and BG. The Control group was fed with a semipurified diet without gangliosides and the BG group was fed with the semipurified diet supplemented with 47 mg/kg of a mixture of bovine brain gangliosides. Intestinal lymphocytes were isolated from mice killed at 3, 7, 14 and 28 days after weaning, and the percentages of spontaneous Th1 as well as Th2 cytokine-secreting lymphocytes were determined using the ELISPOT assay. The BG group animals showed an earlier development in the number of cytokine-secreting cells, which appeared one week later in Control animals. In addition, mice fed with the ganglioside-supplemented diet showed a significantly higher number of Th1 and Th2 cytokine-secreting lymphocytes than Control mice in lamina propria and Peyer's patches lymphocytes at the end of the experimental period (28 days). Our results suggest that dietary gangliosides influence the maturation process of the intestinal immune system that take place during weaning.

Animals↗

PubMed2001

Toxicity of Hg, Cu, Cd, and Cr on early developmental stages of Ciona intestinalis (Chordata, Ascidiacea) with potential application in marine water quality assessment.

The toxicity of mercury, copper, cadmium and chromium on sperm viability, fertilisation, embryogenesis and larval attachment of Ciona intestinalis was examined. Fertilisation rate (FR) showed a small decrease even at the highest metal concentration tested. The median effective concentrations (EC50) reducing rates of embryogenesis and larval attachment by 50% were 54 microg Hg/l (0.27 microM), 46 microg Cu/l (0.72 microM), 838 microg Cd/l (7.46 microM), 10,318 microg Cr/l (198 microM), and 35 microg Hg/l (0.18 microM), 34 microg Cu/l (0.54 microM) and 11,755 microg Cr/l (226 microM), respectively. Therefore, Hg is three times more toxic than Cu (on a molar basis), ca. 30 times more toxic than Cd and ca. 1000 times more toxic than Cr to early stages of C. intestinalis. Rates of larval attachment and embryogenesis were the most sensitive endpoints, although the latter is more advisable for routine assessment of seawater quality because of its greater simplicity. In addition to bivalves and sea-urchins, ascidian embryos can provide biological criteria for seawater quality standards taking into account the sensitivity of a chordate and contributing to the detection of harmful chemicals with no marked effect on the species currently in use in seawater quality bioassays.

Animals↗

PubMed2001

Stabilization/solidification of MSW incineration residues from facilities with different air pollution control systems. Durability of matrices versus carbonation.

This paper discusses the stabilisation/solidification process with Portland cement applied to municipal solid waste incineration residues. Two types of residues were considered: fly ash (FA) produced in an electrostatic precipitator, and air pollution control (APC) residues from a semi-dry scrubber process. Cement pastes with different percentages of FA and APC residues were characterised according to their physical properties, the effect of the hydration products and their leaching behaviour. Portland pastes prepared with APC residues showed a rapid setting velocity in comparison with setting time for those pastes substituted with FA residues. Portland cement hydration was retarded in FA pastes. Leaching test results showed that heavy metals (such as Zn, Pb and Cd) and sulphates are immobilised within the paste, whereas chlorides are only partially retained. The carbonation process increases the leachability of S04(2-) and heavy metals such as Zn and Cr.

Air Pollutants↗

PubMed2000

Weaning induces an increase in the number of specific cytokine-secreting intestinal lymphocytes in mice.

Intestinal immunity differs from systemic immunity in several aspects and is frequently studied separately. In this work we have analysed the frequency of mononuclear cells spontaneously secreting the cytokines IL-2, IL-4, IL-5, IL-6, IL-10, interferon gamma (IFN-gamma) and tumour necrosis factor (TNF-alpha), in Peyer's patches and lamina propria of small intestine in mice by enzyme linked immunosorbent spot (ELISPOT) during 1 month after weaning. We have found a high percentage of spontaneous Th(1)as well as Th(2)cytokine-secreting lymphocytes in both populations, Peyer's patches and lamina propria. An increase in the number of the lymphocytes secreting most of the studied cytokines, at 1 and 2 weeks after weaning, was also observed. These results suggest that the increase in the number of cytokine secreting lymphocytes may be one of the potential mechanisms involved in the development of the intestinal immune system at weaning.

Animals↗

PubMed2000

Comparative toxicity of dissolved metals to early larval stages of Palaemon serratus, Maja squinado, and Homarus gammarus (Crustacea:Decapoda).

The acute lethal toxicities of mercury, copper, and cadmium to the first larval stage of the prawn (Palaemon serratus), spider crab (Maja squinado), and lobster (Homarus gammarus) were tested. Chromium was also tested with the prawn. Mortality was recorded after 48 h (for lobster) or 72 h (for other species) incubation at 18 degrees C, and the median lethal concentrations (LC(50) +/- 95% confidence intervals) per individual and per mass unit were calculated. The LC(50) values were, 74 microg Hg/L, 3,304 microg Cu/L, 1,686 microg Cd/L, 12,486 microg Cr/L for prawn; 72 microg Hg/L, 50 microg Cu/L, 158 microg Cd/L for spider crab; and 48 microg Hg/L, 46 microg Cu/L, 34 microg Cd/L for lobster. Therefore, larvae of spider crab and lobster were markedly more sensitive than prawn to heavy metals and thus more suitable to use in seawater quality bioassays. Of these two species, spider crab is recommended due to its abundance, easier maintenance, and higher fecundity. The mercury LC(50) values for different larval stages of P. serratus (zoea I, II, V, and VI) were obtained, and no ontogenetic change in sensitivity to the metal could be detected.

Animals↗

PubMed2000

Stability and folding of the protein complexes of barnase.

Native-like complexes of proteins, formed by the association of two complementary fragments comprising the entire sequence of the protein, can be used to gain insight into the stability and folding of the intact protein. We have studied the structural, thermodynamic and kinetic properties of four barnase complexes, with the cleavage site at different positions of the amino-acid chain (CB36, at position 36; CB56, at position 56; CB68, at position 68; and CB79, at position 79). The four barnase complexes have native-like structure as shown by fluorescence, far-and near-UV CD, size-exclusion chromatography and NMR. The NMR characterization indicated that the structural changes were mainly located in regions close to the cleavage site. The main core of the protein was fully formed and the overall structure was similar to that of intact barnase. The thermal and chemical denaturation showed that all complexes were substantially destabilized. CB56 displayed two denaturation transitions, probably because of the presence of partially folded conformations around the cleavage site. The rate constant for the association/folding of fragments decreased with the decreasing length of the C-terminal fragment. Thus, the larger the fragment (and, consequently, the larger the amount of residual native-like structure), the faster the association. These findings are consistent with the proposed model of barnase folding.

Bacterial Proteins↗

PubMed2000

Influence of atrial fibrillation on the morbido-mortality of patients on hemodialysis.

BACKGROUND: The consequences of atrial fibrillation (AF) on morbido-mortality of patients on hemodialysis have not been fully explored. The objective of this study was to determine the prevalence of AF in patients on hemodialysis and to evaluate its influence on the development of thromboembolic phenomena (TEP). METHODS: The incidence of AF in 190 patients in our hemodialysis program was assessed, and the patients were followed up for 1 year. Pertinent demographic and biochemical parameters were entered into univariate and multivariate statistical analyses to evaluate associations with overall mortality and TEP such as cerebrovascular accident, transitory ischemic accident, or peripheral embolism. RESULTS: In 13.6% of patients, AF was found; 9.4% of these were of the permanent type. In the multivariate analysis, only increased age was associated with a higher probability of having arrhythmia (odds ratio, 1.10; 95% confidence interval, 1.03-1.17; P =.003). During follow-up, 23% of the patients with AF died compared with 6% of those in sinus rhythm (P <.05), although AF did not appear to be an independent predictive factor for death. Thirty-five percent of the patients with AF and 4% with sinus rhythm had TEP (P <.01). In the multivariate analysis, AF was identified as the only independent predictor for TEP (odds ratio, 8; 95% CI, 2.3-27; P =.0008). CONCLUSIONS: AF is a frequent arrhythmia in patients on hemodialysis, and approximately 1 in 3 hemodialysis patients with AF had thromboembolic complications within 1 year of follow-up. These findings suggest that the consensus contraindication of prophylactic anticoagulation therapy for this group of patients may need to be redefined.

Adult↗

PubMed2000

Therapeutic effects of docosahexaenoic acid ethyl ester in patients with generalized peroxisomal disorders.

Generalized peroxisomal disorders are severe congenital diseases that involve the central nervous system, leading to severe psychomotor retardation, retinopathy, liver disease, and early death. In these disorders, peroxisomes are not normally formed and their enzymes are deficient. Characteristically, plasmalogen synthesis and beta-oxidation of very-long-chain fatty acids (VLCFAs) are affected. We found that patients with generalized peroxisomal disorders have a profound brain deficiency of docosahexaenoic acid (DHA; 22:6n-3) and low DHA concentrations in all tissues and the blood. Given the fundamental role of DHA in neuronal and retinal membranes, a DHA deficiency of this magnitude might be pathogenic. Thus, we studied the possible therapeutic effect of normalizing DHA concentrations in patients with peroxisomal disorders. We chose the DHA ethyl ester (DHA-EE) because of its high degree of purity at daily oral doses of 100-500 mg. This article summarizes the results of treatment of 13 patients with DHA-EE, with some follow-up evidence of clinical improvement. Supplementation with DHA-EE normalized blood DHA values within a few weeks. Plasmalogen concentrations increased in erythrocytes in most patients and after DHA concentrations were normalized, amounts of VLCFAs decreased in plasma. Liver enzymes returned almost to normal in most cases. From a clinical viewpoint, most patients showed improvement in vision, liver function, muscle tone, and social contact. In 3 patients, normalization of brain myelin was detected by magnetic resonance imaging. In 3 others, myelination improved. In a seventh patient, myelination is progressing at a normal rate. These results suggest a fundamental role of DHA in the pathogenesis of Zellweger syndrome. DHA therapy is thus strongly recommended, not only to alleviate symptoms in patients with life-threatening diseases, but also to clarify remaining questions regarding the role of DHA in health and disease.

Brain↗

PubMed2000

Murine CFTR channel and its role in regulatory volume decrease of small intestine crypts.

Cystic fibrosis (CF) is caused by mutations in the secretory Cl(-) channel CFTR (cystic fibrosis transmembrane conductance regulator). Variation in the severity of disease has been attributed to mutations in the CFTR gene that cause different degrees of dysfunction of the CFTR Cl(-) channel. However, studies of mouse models of CF indicate that the severity of intestinal pathology is not correlated with activity of the CFTR chloride channel. This observation suggests that other 'environmental' factors might be important in determining the severity of disease. In this respect, we have identified and characterised an additional cellular defect in intestinal epithelial cells of CF mice, the inability of these cells to regulate their volume after hypotonic challenge. Here, we review the function of murine CFTR as both a Cl(-) channel and as a regulator of volume-dependent homeostatic cell mechanisms.

Animals↗

PubMed1999

[Treatment of generalized peroxisomal disorders with docosahexaenoic acid ethyl ether].

INTRODUCTION: We found that patients with the Zellweger syndrome and other generalized peroxisomal disorders have a dramatic decrease of docosahexaenoic acid (DHA, 22:6n-3) in the blood, brain, retina and other tissues. DHA is believed to play an important role in the brain and retina. DEVELOPMENT: Patients with the Zellweger syndrome and its variants have severe cerebral and retinal defects that could be related to their DHA deficiency. With this rationale, we have been treating peroxisomal-disorder patients with a DHA derivative of a high degree of purity (DHA ethyl ester, > 90% pure) since 1991. So far, we have treated 13 DHA-deficient peroxisomal patients, one with the classic Zellweger syndrome and 12 with milder variants of the disease. This paper presents the follow-up of these DHA-treated patients. In summary, we have found important improvements in liver function, in the plasmalogen levels and in the two ratios 26:0/22:0 y 26:1/22:0, diagnostic of the disease. We have also found clear clinical improvements in most cases. Most significantly, magnetic resonance imaging has shown advances in brain myelination, so far in 6 of the treated patients. CONCLUSION: We strongly recommend treatment with DHA ethyl ester in all DHA-deficient patients with generalized peroxisomal disorders. Logically, treatment should be started as soon as possible, in the hope of preventing cerebral and visual damage.

Brain↗

PubMed1998

Is the malaria diagnosis expensive?

Malaria remains the most important of the tropical diseases, widespread throughout the tropics, but also occurring in many temperate regions. The disease causes a heavy toll of illness and death, among children in endemic areas. It also poses a risk to business travellers, tourists and immigrants and imported cases of malaria are increasingly seen in non-endemic areas. We discuss here how microscopical diagnosis is essential for identifying Plasmodium species responsible of the infection and discarding possible mixed infections. Thus, a correct treatment can be administered in 30 min, avoiding secondary stays and saving important amounts of money. Problems of drug resistance have to be distinguished from those arising due to erroneous diagnosis.

Adult↗

PubMed1998

Non-operative management of traumatic pancreatic pseudocysts associated with pancreatic duct laceration in children.

Objective. To assess the successful non-operative management in traumatic pancreatic pseudocysts (TPP) associated with duct laceration in children. Surgical therapy (cystogastrostomy or distal pancreatectomy with splenic salvage) has been classically considered the treatment of choice for those pseudocysts. Materials and methods. This report presents the clinical and imaging findings in two children with TPP and pancreatic duct disruption observed either on endoscopic retrograde cholangiopancreatography or injection via catheter drainage. Results. Both children responded to long-term cyst drainage. Conclusion. Although the experience is limited, the authors suggest that pancreatic injury associated with duct laceration can respond to non-operative management.

Adolescent↗